Interface, Einsteigerproblem?

[Mario]

Also ist es so richtig?

Delphi-Quellcode:

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  ITest1 = interface
  ['{BC490D6F-306F-4FC5-AF6A-D76B39658B9F}']
    procedure Test1;
  end;

  ITest2 = interface
  ['{BDCB2821-FC57-4729-A1C0-9CEF3A28F72A}']
    procedure Test2;
  end;

  TBaseClass = class(TInterfacedObject, ITest1)
  public
    procedure Test1; virtual;
  end;

  TTestClass = class(TBaseClass, ITest2)
  public
    procedure Test2;
    procedure Test1; override;
  end;


  TForm1 = class(TForm)
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private-Deklarationen }
  public
    { Public-Deklarationen }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

{ TTestClass }

procedure TTestClass.Test1;
begin
  inherited;
  ShowMessage('TTestClass.Test1;');
end;

procedure TTestClass.Test2;
begin
  ShowMessage('TTestClass.Test2;');
end;

{ TBaseClass }

procedure TBaseClass.Test1;
begin
  ShowMessage('TBaseClass.Test1;');
end;

procedure TForm1.Button1Click(Sender: TObject);
var aClass: TBaseClass;
    aInterface1: ITest1;
    aInterface2: ITest2;
begin
  aClass := TTestClass.Create;

  if aClass.QueryInterface(StringToGuid('{BDCB2821-FC57-4729-A1C0-9CEF3A28F72A}'),aInterface2) = 0
  then aInterface2.Test2;
  if aClass.QueryInterface(StringToGuid('{BC490D6F-306F-4FC5-AF6A-D76B39658B9F}'),aInterface1) = 0
  then aInterface1.Test1;
end;

end.